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A coffee filter of mass 1.8kgdropped from a height of 4mreaches the ground with a speed of 0.8m/s. How much kinetic energyKairdid the air molecules gain from the falling coffee filter? Start from the Energy principle, and choose as the system the coffee filter, the Earth and the air.

Short Answer

Expert verified

The loss of kinetic energy is obtained as 69.984×10-3Jand the energy is transferred in air molecules.

Step by step solution

01

Given Information

Mass of coffee filterm=1.8g , heighth=4m , speedv=0.8m/s .

02

Definition of Internal Energy

The potential energy is given by:

U=mgh

Here denotes mass. Theis acceleration due to gravity that is given by9.8m/s2,h stands for height.

The kinetic energy is given by:

k=12mv2

Here,is mass of the object andis the velocity of the object.

03

Calculation of speed which hits the ground

The mass of coffee filter is m=1.8g.

Convert the unit of mass into kg.

m=1.8g10-3kg1g=1.8×10-3kg

Thus, out of all, the observers in situation may feel that Newton’s first law has been violated.

Substitute , m=1.8×10-3kg,g=9.8m/s2andh=4minto the formula of potential energy.

role="math" localid="1657795625494" U=1.8×10-3kg9.8m/s24m=70.56×10-3J

Therefore, the potential energy is 70.56×10-3J.

04

Calculation of Kinetic Energy

Substitutem=1.8×10-3kgandv=0.8m/s andinto the formula of kinetic energy.

k=121.8×10-3kg0.8m/s2=0.576×10-3J

Therefore, the kinetic energy is 0.576×10-3J.

05

Calculation of Loss of Energy

The loss of energy is given by ∆E=PE-KE.

Subtract the obtained kinetic energy from the obtained potential energy to obtain the amount of energy loss.

∆E=PE-KE=70.56×10-3J-0.576×10-3J=69.984×10-3J

The loss of energy is said to be transferred in the air molecules.

Therefore, loss of kinetic energy is69.984×10-3J and energy is transferred in air molecules.

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